I. Field of the Invention
The present invention relates to a tilt sensor for detecting a tilt of an object when the object is tilted.
II. Description of the Prior Art
Conventional tilt measuring devices of this type vary from simple devices such as a level and a device used in an oilstove to visually show horizontality by suspending a counterweight through a chain to a sophisticated one such as a gyroscopic horizon.
Although a simple device such as a level is inexpensive, a tilt can be checked by only a visual observation. Therefore, it is not designed to be used in a control system for resetting a tilted object to a horizontal position. Use of a sophisticated device such as a gyroscopic horizon is limited to an expensive machine such as an aircraft.
Therefore, the present inventors proposed a tilt sensor wherein a permanent magnet a surface of which is coated with a magnetic fluid is arranged inside a hollow portion of a case, and a magnetic sensing element is disposed outside the case, so that when the case is tilted, the permanent magnet disposed therein is moved to the lowest position by its weight, and hence magnetism detected by the magnetic sensing element changes, thereby detecting that the case is tilted (Japanese Patent Application No. 61-169930, U.S. Application No. 074,249, and EPC Application No. 87110176.2).
According to the above invention, a tilt can be detected with high precision by a simple arrangement, and its detection signal can be applied to a control system for attitude control or the like.